In the soft drink industry, when reusable glass bottles were the standard container, it was conventional to apply a crown or crimp on cap to the glass bottle after the container had been filled. However, in recent years the soft drink industry has been selling a greater percentage of its output in either nonreusable glass bottles or in PET bottles which are plastic bottles having flexible cylindrical sides and an upper neck provided with a radially extending flange adjacent the open top of the container, a typical example being a two liter container. Three common closures are now used on these containers. The first of these is a cap which is quite similar to the conventional crimp on cap but which can be unscrewed by the user. While this design is widely accepted by the brewing industry, it does have the disadvantage of not showing evidence of tampering. In order to provide the purchaser with evidence of tampering with respect to the soft drinks, two designs provided with tamper evident bands have been widely commercialized. The first of these designs is a plastic cap provided with a heat shrink tamper evident band, the plastic cap being screwed onto the container, the container then being passed through a heating tunnel which causes the tamper evident band to shrink about a collar on the container. When this form of closure is subsequently opened by the user, the tamper evident band is supposed to separate, but almost always stays with closure when removed from bottle. A second form of tamper evident closure also used on both glass containers and PET bottles is a roll on aluminum cap which is in its initial form, a closed cylindrical shape, the cylinder of aluminum being rolled about the threads provided on the container to close it to the container. However, this design also has the disadvantage in that frequently the tamper evident band will not tear away from the upper part of the closure when the container is being opened thus not providing the purchaser with the desired evidence that the contents have been tampered with. Other disadvantages of this form of closure are well known to those skilled in the art. In each of the foregoing tamper evident designs it is customary to apply the closure initially to the container by passing the container underneath the closure wherein the closure is tipped onto the top of the container. This is possible because both the plastic closure having the heat shrink tamper evident band and the aluminum closure which is to be rolled onto the threads of the container initially have relatively large bottom openings which are subsequently reduced in diameter during the closure process.
A third design has been developed which includes both a plastic cap and an integral tear away tamper evident band. As the design has a smaller collar it is necessary to apply the cap axially to the opening of the bottle.
Of course it is well known in the capping industry to apply screw-on caps to glass bottles and metal cans. One well known machine for applying screw-on caps to such containers is illustrated in U.S. Pat. No. 3,537,231 and which is sold under the trade name of CAPEM by Consolidated Packaging Machinery. This form of machine has a turret provided with a number of work stations, each work station being provided with a vertically shiftable and rotatable chuck for applying the closures to the containers, one such chuck being illustrated in U.S. Pat. No. 4,178,733. The machine may be so designed that the chuck picks up the closure from a desired location on a cap pickup plate and then screws it on to the container, the jaws of the chuck being so designed that they will open after the proper torque has been applied to the closure. CAPEM type machines are suitable for applying closures to PET bottles. For example, when applying tamper evident closures of the first two types set forth above, relatively low torques are required to apply these closures and head pressure alone is sufficient to prevent rotation. However, higher torque forces are required when applying the third design of closure or other similar closures, all of which have a relatively small diameter tamper evident band which must be cammed over the tamper evident band retaining ring on the container while the closure is being screwed onto the container. While it is conventional to provide a container engaging device which moves in from the side and engages the container to prevent the container from rotating while a closure is being applied, it is not desirable to use such container engaging devices in the soft drink industry. Thus, it is desirable in the soft drink industry to place the containers as close together as possible on the conveyor within the capping machine to increase the output of the capping machine. This means that each rotatable chuck on the capping machine must be spaced relatively close by to adjacent chucks. However, known container engaging devices which move in from the sides require a greater spacing between chucks than that normally accepted in the soft drink industry. Also such engaging devices are relatively expensive.